1. Field of the Invention
The invention relates in general to an electrostatic discharge (ESD) protection circuit, and more particularly to a method using the corresponding voltage of the electrostatic charges to have the transistor be conducted for the electrostatic charges to be discharged promptly.
2. Description of the Related Art
Electrostatic discharge is a transfer of electrostatic deposition of electrostatic charges between different objects. The occurrence of electrostatic discharge is normally very short and has to be calculated in nano-seconds. To generate a high current within such a short time, the current is normally as high as several amperes. If a current of high amperes flows through a semiconductor integrated circuit, damage would occur.
Therefore, in a semiconductor circuit, the ESD protection circuit disposed between power lines must be able to provide a discharge path through which the generated high-voltage static electricity is discharged to protect the semiconductor integrated circuit from being damaged. Conventional liquid crystal display has an ESD protection circuit disposed between each gate line and common electrode and between each data line and common electrode to protect each pixel transistor from being damaged by the high-voltage static electricity generated. Referring to FIG. 1, a circuit diagram of an ESD protection circuit of a conventional liquid crystal display is shown. The ESD protection circuit 100 is coupled to between a gate line GL and a common electrode Vcom, comprising 6 diodes, namely, D (1)˜D (6). A first discharge path R1 is formed by diodes D (1)˜D (3) and a second discharge path R2 is formed by diodes D (4)˜(6). When static electricity is generated by the gate line GL, the electrostatic current is discharged to the common electrode Vcom via the discharge path R1, or the electrostatic current is discharged to the gate line GL via the discharge path R2 when the common electrode Vcom generates static electricity.
According to the design of ESD protection circuit 100, diodes D (1)˜D (6) are implemented through an amorphous silicon manufacturing process. However, due to a large channel width, the area of the circuit layout of the ESD protection circuit 100 increases accordingly. Consequently, the area of liquid crystal display panel would increase and cannot be reduced. The discharge rate of the conventional ESD protection circuit 100 is not fast enough to discharge electrostatic charges of high voltages, and falls short of providing protection to pixel circuits.